Design of e-cash system using group signature

Abstract

Researches on the secure electronic cash (e-cash) systems have been carried on with the proliferation of the Internet and e-commerce. Subsequently, various systems and schemes have been proposed in the literature. Among them, E-commerce is the most pervasive and prominent area. E-commerce is the business process of selling and buying the products, goods and services by on-line communications. It can be highly beneficial in reducing business costs and in creating opportunities for new or improved customer services: customers feel convenience to order and are able to collect plenty of information to compare analogous products which are manufactured from the different vendors, vendors can trade globally and find new market with cut down investment, financial facilities like bank can reduce transaction cost. Unlike ordinary signatures, group signatures allow a group member to create anonymous (and unlinkable) signatures. Upon verifying a signature, the verifier does not learn the identity of the group member that created the signature. However, should the need arise, a group signature can be ``opened`` by a trusted party and the identity of the member who created the signature will be revealed. Group signatures, and particularly group blind signatures (which incorporate the properties of both blind signatures and group signatures), have many applications such as e-commerce. After Lysyanskaya and Ramzan[23]have proposed group blind signature in FC ``98, there have been several e-cash system proposed[34,35,25,21,28]using group blind signatures. The anonymity and unlikability afforded by group signatures suggests that they may have a role to play in anonymous e-cash scheme design. The existing proposals have utilised group signatures in different roles, where the group has been formed from the banks that issued the e-coins, the customers that spend the e-coins, and indeed the coins themselves. In Eurocrypt 2003, Kiayias and Yung[22]introduced a generic way of tu...